scholarly journals Assessment of Tube Well Pumping Test Performance on Different Geological Formation

Author(s):  
Muhd Syamir Sobri ◽  
◽  
Ahmad Khairul Abd Malik ◽  
Mohd Firdaus Md Dan ◽  
Hamzah Hussin ◽  
...  

Water supply-demand is increasing in line with the increment in population. Natural water resources are declining due to reduction of water catchment areas, river pollution and drought. This causes the raw water quantity and quality to decrease and increase water treatment costs. Groundwater usage may be able to solve this problem due to its less polluted nature which requires less treatment. The groundwater is preserved in aquifer within the geological formations, i.e., in the alluvium and fractured-rock. However, the groundwater yield of each formation is unknown unless tube well is constructed and pumping test are performed. This study aim to evaluate the tube well performance via pumping test on two different geological formations. This research focuses on the effect of transmissivity, hydraulic conductivity, and efficiency of the aquifer, which are step-drawdown test, constant-rate test and recovery test in tube well in geological formation of alluvium and fractured rock. Three well-pumping tests at each formation were conducted at IBS Universiti Malaysia Kelantan (UMK), Kelantan, Sekolah Kebangsaan Chantum, Kelantan, Sekolah Menengah Kebangsaan Agama Tok Bachok, Kelantan, FRU Wakaf Tapai, Terengganu, Kampung Dada Kering, Kuala Lipis, Pahang, and Kampung Seri Gunung Pulai, Johor, respectively. The aquifer efficiency obtained from the relationship between transmissivity and hydraulic conductivity. The suggested value of 75% efficiency is selected to present the well’s efficiency. The wells efficiency indicate that the alluvium formation has roughly uniform output between 9.39m3/h, 11.23m3/h and 23.38m3/h. Meanwhile in the fractured rock formation the efficiency was highly varied between sites, the highest is 32.33m3/h and the other two sites obtained has low output of 3.44 m3/h and 1.00m3/h respectively. The alluvium aquifer showed uniform water production compared to fractured hard rock aquifer. Meanwhile the water quantity in the fractured hard rock formation is unpredicted, which subjected to the fractured rock characteristic.

2014 ◽  
Vol 931-932 ◽  
pp. 823-828 ◽  
Author(s):  
Thidarat Cotanont ◽  
Chalong Buaphan ◽  
Kamonporn Kromkhun

Fractured rock aquifers provide the most extensive groundwater resources in Northeast Thailand. The hydraulic conductivity (K) of these aquifers controls the flow of water and is therefore, an essential parameter for groundwater modeling and management. K values may be directly determined by conducting pumping tests at the aquifer or by performing fracture analysis using data acquired from outcrops. The K value at outcrop should be greater than that at aquifer of deeper position due to the effect of aperture reduction by overburden compression. The goal of this study was therefor to find the correlation between K values determined from outcrop with those directly measured at an aquifer. This study was conducted on the Phu Phan sandstone aquifer at the Huay Luang watershed, Udon Thani Province of Northeast Thailand. The orientation, aperture, and spacing of fractures were measured at four outcrops and used for determining the K values by fracture analysis. Single well pump test data from 17 wells in the Phu Phan aquifer (30-120 m depth) were analyzed to obtain transmissivity (T) and K. Both sets of the K values, from outcrop and aquifer, were correlated using the plotting position of Weibull. Both plots were linear on a semi-log scale but the outcrop curve was steeper. Lognormal distributions fitted both plotting positions quite well. These results show that for the same probability value, K values found from the pumping test to be about an order of magnitude smaller than K values determined from outcrop data.


1975 ◽  
Vol 12 (1) ◽  
pp. 23-43 ◽  
Author(s):  
G. E. Grisak ◽  
J. A. Cherry

Fractures in glacial till and glaciolacustrine clay were observed in excavations up to 20 ft (6.1 m) in depth and in drill cores at the Whiteshell Nuclear Research Establishment (WNRE) in southeastern Manitoba. The fractures are characteristically coated with carbonate and oxide precipitates, which indicate groundwater movement through the fractures. The fractures impart an effective bulk hydraulic conductivity to the clay–loam till and lacustrine clay, as evidenced by tritium tracer experiments and piezometer responses in the till and clay to pumping of an underlying sandy aquifer.The intergranular hydraulic conductivity of clay–loam till and glaciolacustrine clay in the Interior Plains, as determined from laboratory consolidation test data, is in the range of 2 × 10−10 to 9 × 10−11 ft s−1 (6 × 10−9 to 2.7 × 10−9 cm s−1). The bulk hydraulic conductivity of the fractured clay–loam till at WNRE, as determined from finite-element mathematical modeling, is about 6 × 10−9 ft s−1 (1.8 × 10−7 cm s−1). The model value represents the effective hydraulic conductivity imparted to the till by the fractures.Seven pumping tests, ranging in duration from 8.75 to 120 h were conducted on the sandy aquifer and drawdown data in the aquifer were analyzed to obtain the hydraulic conductivity and storativity of the aquifers.A 32 day pumping test on the aquifer showed that many of the piezometers in the till and clay respond quickly and strongly to the aquifer drawdown, while others show no noticeable response. The responding piezometers intersect open fractures whereas the others do not. Analysis of the piezometer drawdowns during the long-term pumping test using the Neuman and Witherspoon ‘ratio’ method indicates that the rapid piezometer drawdowns in the confining layers can be accounted for by assigning specific storativity values in the range of 1 × 10−5 to 5 × 10−6 ft−1 (3 × 10−5 to 1.5 × 10−5 m−1) to the clay–loam till and lacustrine clay. These values are typical of fractured rock. If intergranular specific storage values are used, the calculated piezometer drawdowns are very small or negligible.


2015 ◽  
Vol 8 (7) ◽  
pp. 2167-2185 ◽  
Author(s):  
A. P. S. Selvadurai ◽  
A. P. Suvorov ◽  
P. A. Selvadurai

Abstract. The paper examines the coupled thermo-hydro-mechanical (THM) processes that develop in a fractured rock region within a fluid-saturated rock mass due to loads imposed by an advancing glacier. This scenario needs to be examined in order to assess the suitability of potential sites for the location of deep geologic repositories for the storage of high-level nuclear waste. The THM processes are examined using a computational multiphysics approach that takes into account thermo-poroelasticity of the intact geological formation and the presence of a system of sessile but hydraulically interacting fractures (fracture zones). The modelling considers coupled thermo-hydro-mechanical effects in both the intact rock and the fracture zones due to contact normal stresses and fluid pressure at the base of the advancing glacier. Computational modelling provides an assessment of the role of fractures in modifying the pore pressure generation within the entire rock mass.


2018 ◽  
Vol 482 (1) ◽  
pp. 241-260 ◽  
Author(s):  
V. Tsitsopoulos ◽  
S. Baxter ◽  
D. Holton ◽  
J. Dodd ◽  
S. Williams ◽  
...  

AbstractThe Prototype Repository (PR) tunnel is located at the Äspö Hard Rock Laboratory near Oskarshamn in the southeast of Sweden. In the PR tunnel, six full-sized deposition holes (8.37 m deep and 1.75 m in diameter) have been constructed. Each deposition hole is designed to mimic the Swedish reference system for the disposal of nuclear fuel, KBS-3V. The PR experiment is designed to provide a full-scale simulation of the emplacement of heat-generating waste. There are three phases to the experiment: (1) the open tunnel phase following construction, where both the tunnel and deposition holes are open to atmospheric conditions; (2) the emplacement of canisters (containing heaters), backfill and seal in the first section of the tunnel; and (3) the emplacement of canisters, backfill and seal in the second section of the tunnel. This work describes the numerical modelling, performed as part of the engineered barrier systems (EBS) Task Force, to understand the thermo-hydraulic (TH) evolution of the PR experiment and to provide a better understanding of the interaction between the fractured rock and bentonite surrounding the canister at the scale of a single deposition tunnel. A coupled integrated TH model for predicting the wetting and the temperature of bentonite emplaced in fractured rock was developed, accounting for the heterogeneity of the fractured rock. In this model, geometrical uncertainties of fracture locations are modelled by using several stochastic realizations of the fracture network. The modelling methodology utilized information available at early stages of site characterization and included site statistics for fracture occurrence and properties, as well as proposed installation properties of the bentonite. The adopted approach provides an evaluation of the predictive capability of models, it gives an insight of the uncertainties to data and demonstrates that a simplified equivalent homogeneous description of the fractured host rock is insufficient to represent the bentonite resaturation.


2020 ◽  
Vol 28 (8) ◽  
pp. 2657-2674
Author(s):  
Markus Theel ◽  
Peter Huggenberger ◽  
Kai Zosseder

AbstractThe favorable overall conditions for the utilization of groundwater in fluvioglacial aquifers are impacted by significant heterogeneity in the hydraulic conductivity, which is related to small-scale facies changes. Knowledge of the spatial distribution of hydraulically relevant hydrofacies types (HF-types), derived by sedimentological analysis, helps to determine the hydraulic conductivity distribution and thus contribute to understanding the hydraulic dynamics in fluvioglacial aquifers. In particular, the HF-type “open framework gravel (OW)”, which occurs with the HF-type “bimodal gravel (BM)” in BM/OW couplings, has an intrinsically high hydraulic conductivity and significantly impacts hydrogeological challenges such as planning excavation-pit drainage or the prognosis of plumes. The present study investigates the properties and spatial occurrence of HF-types in fluvioglacial deposits at regional scale to derive spatial distribution trends of HF-types, by analyzing 12 gravel pits in the Munich gravel plain (southern Germany) as analogues for outwash plains. The results are compared to the reevaluation of 542 pumping tests. Analysis of the HF-types and the pumping test data shows similar small-scale heterogeneities of the hydraulic conductivity, superimposing large-scale trends. High-permeability BM/OW couples and their dependence on recognizable discharge types in the sedimentary deposits explain sharp-bounded small-scale heterogeneities in the hydraulic conductivity distribution from 9.1 × 10−3 to 2.2 × 10−4 m/s. It is also shown that high values of hydraulic conductivity can be interpolated on shorter distance compared to lower values. While the results of the HF-analysis can be transferred to other fluvioglacial settings (e.g. braided rivers), regional trends must be examined with respect to the surrounding topography.


Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Chi Yao ◽  
Chen He ◽  
Jianhua Yang ◽  
Qinghui Jiang ◽  
Jinsong Huang ◽  
...  

An original 3D numerical approach for fluid flow in fractured porous media is proposed. The whole research domain is discretized by the Delaunay tetrahedron based on the concept of node saturation. Tetrahedral blocks are impermeable, and fluid only flows through the interconnected interfaces between blocks. Fractures and the porous matrix are replaced by the triangular interface network, which is the so-called equivalent matrix-fracture network (EMFN). In this way, the three-dimensional seepage problem becomes a two-dimensional problem. The finite element method is used to solve the steady-state flow problem. The big finding is that the ratio of the macroconductivity of the whole interface network to the local conductivity of an interface is linearly related to the cubic root of the number of nodes used for mesh generation. A formula is presented to describe this relationship. With this formula, we can make sure that the EMFN produces the same macroscopic hydraulic conductivity as the intact rock. The approach is applied in a series of numerical tests to demonstrate its efficiency. Effects of the hydraulic aperture of fracture and connectivity of the fracture network on the effective hydraulic conductivity of fractured rock masses are systematically investigated.


2015 ◽  
Vol 802 ◽  
pp. 634-639 ◽  
Author(s):  
Mohd Nordin Adlan ◽  
Mohamad Razip Selamat ◽  
Siti Zahirah Othman

For a developing country such as Malaysia, riverbank/bed filtration (RBF) technology is still new and only few efforts have been made to understand the RBF mechanism and processes. Soil characteristics play important roles in determining the water quality and the ability of water to be abstracted from the wells during RBF process. A research has been carried out to identify the characteristic of riverbank soil at different layers in the pumping well (PW) borehole at Kota Lama Kiri, Kuala Kangsar, Perak, Malaysia. Soil samples were collected during the development of PW for RBF application. The maximum depth of PW was 8.50 metre. The soil samples were transported to Geotechnical Engineering Laboratory, School of Civil Engineering, Universiti Sains Malaysia and the properties were determined by a series of laboratory test. Soil particle size distribution (PSD) and hydraulic conductivity were obtained from sieve analyses and constant head test with reference to BS 1377: Part 1-9;2:1990. Laboratory results show that the value of Cu(coefficient of uniformity) for the soil samples within the borehole of PW was found to be within the range of 2.00 to 10.00 while the value of Cc(coefficient of gradation) lies in the ranges of 0.06-1.19. The One Way Analyses of Variance test was performed using Minitab statistical packages and the results indicate that the p-value was 0.996, where there was no significance difference between the mean sizes of soil samples within the PW. The hydraulic conductivity, k for PW ranges between 0.10-0.91 cm/s. Soil samples from depth 6.00-7.00 metres has the highest hydraulic conductivity, which is 0.91 cm/s. The overall well production from the pumping test was found 112.10 m3/hr.


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